In the Pacific Northwest, forest roads have the potential to cause significant environmental degradation, especially to water resources due to increased sediment production. The goal of this research is to improve the understanding of road degradation during hauling by improving our understanding of the aggregate degradation process. We correlate the wear rates to standard material property tests that may allow for improved prediction of the impacts from forest roads based on the selection of aggregate surfacing. Finally, we determine the changes in stress distribution between the subgrade and aggregate interface. High-, medium-, and low-quality aggregates were used from three quarries in western Oregon for this project. These aggregates are indicative of the range of materials used on forest roads in the region. Two material property tests, namely the Los Angeles (LA) abrasion and micro-Deval tests, were used to determine their ability to predict aggregate performance during hauling by relating values for aggregate wear to these aggregate properties. Eighteen nonwoven geotextile bags were created, measuring 60 cm (two-feet long) and 20 cm (eight inches) in diameter, with a pore size equivalent to a 0.149 mm (# 100) sieve. They were filled with a known quantity and particle size distribution of aggregate and embedded into a newly constructed forest road. Stress gages were installed in the road surface between the aggregate and subgrade levels to record the changes in stress at the subgrade level. Samples were subjected to three levels of traffic (500, 950, and 1500 passes) using a loaded dump-truck that had a steering axle and one tandem drive axle, weighing 25,038 kg or 55,200 lb. The results showed that less breakage occurred with the medium- and high-quality aggregates than the low-quality aggregate. There was a correlation between the material property test (either the micro-Deval or the LA abrasion test) and the fine index, indicating the predictability of these tests in terms of aggregate performance. Finally, the higher quality aggregate was able to better distribute the stresses from the wheel better than the lower quality aggregate and was able to reduce the stress reaching the subgrade. Although the results are limited to the three types of rock used in this study, they indicate the ability of the high-quality aggregate to lessen the environmental impacts from forest roads.

中文翻译：

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预测俄勒冈州西北部森林公路的总退化

在西北太平洋地区，森林公路有可能造成严重的环境退化，特别是由于增加的泥沙产生而导致水资源退化。这项研究的目的是通过增进我们对骨料降解过程的理解，来增进对牵引过程中道路退化的认识。我们将磨损率与标准材料性能测试相关联，这些测试可以基于选择的集料表面来改进对林道影响的预测。最后，我们确定路基和骨料界面之间的应力分布变化。此项目使用了俄勒冈州西部三个采石场的高，中，低质量骨料。这些总量表明该地区林道使用的材料范围。两次材料性能测试，通过将骨料的磨损值与这些骨料的性能相关联，使用洛杉矶（LA）磨耗试验和微时效试验来确定其预测牵引过程中骨料性能的能力。制作了18个非织造土工布袋，直径为60厘米（两英尺长），直径为20厘米（八英寸），孔径相当于0.149毫米（＃100）筛。它们充满了已知数量和粒度分布的骨料，并嵌入到一条新建的林道中。将应力计安装在骨料和路基之间的路面上，以记录路基上的应力变化。使用一个装有转向轴和一个串联驱动轴，重量为25038千克或55200磅的自卸卡车，对样品进行三个级别的运输（500、950和1500次通过）。结果表明，中，高品质骨料的破损少于低品质骨料。材料性能测试（微磨损测试或LA磨损测试）与精细指数之间存在相关性，表明这些测试在集料性能方面的可预测性。最后，与较低质量的骨料相比，较高质量的骨料能够更好地分配来自车轮的应力，并且能够减少到达路基的应力。尽管结果仅限于本研究中使用的三种类型的岩石，但它们表明高质量骨料具有减轻林道对环境的影响的能力。材料性能测试（微磨损测试或LA磨损测试）与精细指数之间存在相关性，表明这些测试在集料性能方面的可预测性。最后，与较低质量的骨料相比，较高质量的骨料能够更好地分配来自车轮的应力，并且能够减少到达路基的应力。尽管结果仅限于本研究中使用的三种类型的岩石，但它们表明高质量骨料具有减轻林道对环境的影响的能力。材料性能测试（微磨损测试或LA磨损测试）与精细指数之间存在相关性，表明这些测试在集料性能方面的可预测性。最后，与较低质量的骨料相比，较高质量的骨料能够更好地分配来自车轮的应力，并且能够减少到达路基的应力。尽管结果仅限于本研究中使用的三种类型的岩石，但它们表明高质量骨料具有减轻林道对环境的影响的能力。与较低质量的骨料相比，较高质量的骨料能够更好地分配来自车轮的应力，并且能够减少到达路基的应力。尽管结果仅限于本研究中使用的三种类型的岩石，但它们表明高质量骨料具有减轻林道对环境的影响的能力。与较低质量的骨料相比，较高质量的骨料能够更好地分配来自车轮的应力，并且能够减少到达路基的应力。尽管结果仅限于本研究中使用的三种类型的岩石，但它们表明高质量骨料具有减轻林道对环境的影响的能力。